A bovine respiratory disease similar to farmer's lung in man

Wiseman, Alasdair (1978) A bovine respiratory disease similar to farmer's lung in man. PhD thesis, University of Glasgow.

Abstract

During a cinico-pathological investigation of fog fever, precipitating antibodies to Micropolyspora faeni were detected in sera from ten hay-fed housed cattle that had developed acute respiratory disease but they were not detected in 12 cattle that had developed classical pasture-associated fog fever. A case of "indoor" fog fever was subjected to detailed investigation and it was found to be very similar clinically, epidemiologically, pathologically and serologically to acute farmer's lung in man. The disease in cattle was subsequently called "bovine farmer's lung". The clinical signs of bovine farmer's lung had developed suddenly in 18 cases (acute form) while in 27 animals they had developed insidiously (chronic form). With acute farmer's lung there were obvious constitutional signs (agalactia, anorexia) in addition to respiratory distress whereas with the chronic form the major presenting signs were almost wholly referable to the respiratory system (coughing, hyperpnoea). On admission to the Veterinary School, the clinical differences between the two forms of the disease were not very great because of the time that had elapsed since the animals had first been seen to be ill. The 45 clinical cases of bovine farmer's lung were admitted from 29 farms and on six of these farms the farmers suffered from farmer's lung while on another seven they experienced an adverse clinical reaction during, or soon after, working with mouldy hay. The keeping of dairy cattle tied up in byres was closely associated with the development of farmer's lung in their attendants. The prevalence of bovine farmer's lung was higher in dairy than in beef cattle except in Westmorland where the opposite was found. Every clinical case had been admitted from the mainly hilly areas of north-west Britain where there is often rain during the haymaking season. Only mouldy hay was associated with the development of clinical disease although on one farm, where only silage had been fed, precipitins to M. faeni developed in a single cow as a result of her having been fed mouldy rolled wet-stored barley. During the first year of a serological investigation, great variation in the prevalence of precipitins to M. faeni was found between selected herds. The prevalence of precipitins was significantly higher at the beginning of winter in herds selected because the farmer suffered from farmer's lung than it was in the other herds and, during the winter, significantly more cattle developed precipitins in these "farmer's lung" herds. !n contrast during the second winter, a significant increase in the prevalence of precipitins did not occur in any of the herds because particularly mouldy hay had not been fed. Considering both years of the study, it was found that the prevalence of precipitins in a herd at the end of winter v/as determined by the mouldiness of the hay and that the mouldiness of the hay was closely associated with the number of raindays in July. During the summer between the two winter housing periods referred to above, the prevalence of precipitins decreased in every herd. It was deduced that regular exposure to mouldy hay dust had a cumulative effect because the prevalence of precipitins was significantly greater in herds in which farmer's lung had been confirmed, either in the cattle or in the farmer, than in the other herds. There was a positive correlation between the age of the cattle sampled and the prevalence of precipitins as well as between age and the number of clinical cases of bovine farmer's lung. There was also a good correlation between the prevalence of precipitins at the end of winter and the frequency of coughing in the herd.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Adviser: W IM McIntyre
• Keywords: Animal diseases
• Date of Award: 1978
• Depositing User: Enlighten Team
• Unique ID: glathesis:1978-73786
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 14 Jun 2019 08:56
• Last Modified: 14 Jun 2019 08:56
• URI: https://theses.gla.ac.uk/id/eprint/73786